I fostered a dog who hated the car and would puke in it. I started taking her on car trips around the block every night before our nightly walk. The rides were about 2 minutes. She got so she could go for 12 or so minutes after just a week. I know that eventually she became fine.

Maybe someone else could recommend herbal treatments to help with that too. (I know there are some, I just don't know what they are).

The best thing is to do short frequent car trips gradually increasing the time.

Starting with short trips and gradually making them longer as she adjusts is good advise. It's always wise to not feed of water for some time before an anticipated ride as well. If there's nothing in the tummy, then they are less likely to be nauseaus. Did you know that Dramamine or Bonine can be given to lessen car sickness? You should call your vet (have your dog's weight handy) for a proper dosage. Many dogs do outgrow it, though some take longer than others. Good luck!